The invention concerns a vane for a pump or a compressor, in particular, for a single-vane vacuum pump having a pot-shaped housing and being provided with a rotor which is eccentrically and rotatably mounted in the housing, wherein the vane is mounted in the rotor in such a fashion that it can be displaced orthogonally with respect to the axis of rotation, and abuts with its free ends against the inner circumferential surface of the housing, wherein the vane has a closed surface, at least in the sections projecting past the rotor, in the direction of the inner circumferential surface, and the surface is formed by an external wall which is provided with a coating.
Single-vane vacuum pumps are well known. DE 100 46 697 A1 discloses e.g. a vane vacuum pump comprising the features of the pre-characterizing part of claim 1. A vane for a pump of this type is also disclosed in WO 2004/074687 A2. One embodiment of the vane disclosed in this document consists of a high-strength thermosetting material which is coated with a wear-resistant thermosetting material. This combines the properties of the two thermosetting materials, thereby producing a high-strength vane which has a wear-resistant surface.
A vane of this type is held in a slot located in the rotor and, upon rotation of the rotor, oscillates within the slot at a relatively high speed. Since the vane must be held in a fluid-tight fashion in the slot, but the play should be sufficiently large to ensure that the friction forces are acceptably small, a compromise must be found between leakage loss between the pressure space and the vacuum space and wear on the vane and the rotor.
The invention is based on the object of providing a vane for a vane pump which has even less wear and can be guided as tightly as possible in the rotor.